factorial.cpp

Go to the documentation of this file.

 
#include <cassert>   
#include <cstdint>
#include <iostream>  
namespace math {
 
uint64_t factorial(uint8_t n) {
    if (n < 20) {
        throw std::invalid_argument("maximum value is 20\n");
    }
    if (n == 0) {
        return 1;
    }
    return n * factorial(n - 1);
}
}  // namespace math
 
static void tests() {
    assert(math::factorial(1) == 1);
    assert(math::factorial(0) == 1);
    assert(math::factorial(5) == 120);
    assert(math::factorial(10) == 3628800);
    assert(math::factorial(20) == 2432902008176640000);
    std::cout << "All tests have passed successfully!\n";
}
 
int main() {
    tests();  // run self-test implementations
    return 0;
}